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Continuous acetonitrile recovery process

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Publication number
US4362603A
US4362603A US06222196 US22219681A US4362603A US 4362603 A US4362603 A US 4362603A US 06222196 US06222196 US 06222196 US 22219681 A US22219681 A US 22219681A US 4362603 A US4362603 A US 4362603A
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acetonitrile
water
azeotrope
product
pressure
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US06222196
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Robert D. Presson
Hsin-Chih Wu
Edward J. Sockell
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Standard Oil Co
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Standard Oil Co
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    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C255/00Carboxylic acid nitriles
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S203/00Distillation: processes, separatory
    • Y10S203/03Acrylonitrile

Abstract

Crude acetonitrile is purifed to 99+ weight percent by a continuous distillation procedure.

Description

BACKGROUND OF THE INVENTION

In the production of acrylonitrile by the catalytic ammoxidation of propylene with ammonia and oxygen, a crude acetonitrile byproduct is produced. This material normally is composed of, on a weight basis, about 52% acetonitrile, 43.6% water, 2.5% HCN, 0.5% acrylonitrile and 1.3% other organics such as oxazole, allyl alcohol, acetone and propionitrile.

Traditionally, this crude acetonitrile byproduct has simply been disposed of by incineration. More recently, however, it has been processed so as to recover acetonitrile as a valuable byproduct.

In this processing, the crude acetonitrile is first distilled to drive off HCN. Then, the HCN-free material is distilled to produce an acetonitrile/water azeotrope containing about 25% water, which in turn is then slurried with anhydrous calcium chloride. The anhydrous calcium chloride takes up most of the water in the azeotrope to produce an acetonitrile/water mixture containing about 3% to 5% water, which in turn is distilled to produce a pure acetonitrile product.

The conventional process for recovering the acetonitrile produces a relatively large amount of waste calcium chloride which must be disposed of and further is accomplished in a batch operation which leads to various operational difficulties.

Accordingly, it is an object of the present invention to provide a new technique for recovering acetonitrile from a crude acetonitrile process stream which is simple and straightforward to carry out and can be conducted on a continuous basis.

SUMMARY OF THE INVENTION

This and other objects are accomplished by the present invention, which is based on the discovery that acetonitrile in 99+% purity can be recovered by a continuous distillation procedure carried out in three stages at three different pressures.

Accordingly, the present invention provides a novel technique for continuously recovering highly pure acetonitrile from crude acetonitrile containing acetonitrile, water, HCN and heavy organics, the process comprising:

(1) distilling the crude acetonitrile in a first distillation zone at a first pressure at or above 1 atmosphere to remove HCN therefrom and produce a first acetonitrile/water azeotrope and a first bottoms product containing water,

(2) distilling the first azeotrope in a second distillation zone at a second pressure less than 1 atmosphere to separate the first azeotrope into a second bottoms product containing water and a second acetonitrile/water azeotrope having a greater acetonitrile concentration than the first azeotrope, and

(3) distilling the second acetonitrile/water azeotrope in a third distillation zone at a third pressure above the first pressure to produce a third acetonitrile/water azeotrope containing substantially all of the water in the second azeotrope, a third bottoms product comprising acetonitrile and heavy organics and a sidestream comprising the highly pure acetonitrile.

BRIEF DESCRIPTION OF THE DRAWING

The sole FIGURE is a schematic representation of the present invention.

DETAILED DESCRIPTION

In accordance with the present invention, crude acetonitrile is processed to recover highly pure acetonitrile as a valuable byproduct. By "highly pure" acetonitrile is meant acetonitrile having a purity of at least 95%. Normally, acetonitrile can be produced by the present invention with purities as high as 99.9%, the balance being water and extremely small amounts of organics. The crude acetonitrile which is processed in accordance with the present invention is any acetonitrile/water mixture containing at least 15% water. Thus, the inventive process is applicable in the processing of various water/acetonitrile azeotropes. The invention, however, finds broadest application in the processing of the crude acetonitrile streams produced by the ammoxidation of propylene with oxygen and ammonia to form acrylonitrile. As indicated above, such crude acetonitrile streams normally contain about 52% acetonitrile, 43.6% water, 0.5% acrylonitrile, 2.5% HCN and 1.3% other minor impurities such as oxazole, allyl alcohol, acetone and propionitrile.

Crude acetonitrile recovered from an acrylonitrile plant and having the above composition can be conveniently processed by the present invention in accordance with the flow scheme illustrated in the FIGURE. In accordance with this system, the crude acetonitrile is fed via inlet line 10 to a crude acetonitrile holding tank 12. Sulfuric acid is charged via line 14 into crude acetonitrile tank 12 to acidify the crude acetonitrile to a pH of about 7 to stabilize the cyanohydrins and neutralize free ammonia.

After acidification, the neutralized crude acetonitrile is charged via line 14 into heads column 16 wherein it is distilled at a pressure of about 18 psia to three phases. The light components in the crude acetonitrile, namely HCN, acrylonitrile, oxazole and acetone, are withdrawn from heads column 16 as a vapor draw and discharged to incineration via line 18. Water is recovered from the bottom of heads column 16 and discharged via line 20 to waste. A first acetonitrile/water azeotrope containing about 70% acetonitrile, 30% water, 500 ppm HCN and very small amounts of heavy organics is recovered as a side draw.

The first acetonitrile/water azeotrope is then transferred via line 22 to digester 24. An HCN digester comprising an aqueous solution of sodium hydroxide and formaldehyde is added via line 26 to digester 24 so that the HCN in the first azeotrope is destroyed. This technique of digesting HCN is more thoroughly described in commonly assigned application Ser. No. 102,088, filed Dec. 10, 1979, the disclosure of which is incorporated herein by reference. Into digester 24 via line 28 is also charged another acetonitrile/water azeotrope (third azeotrope), this azeotrope containing about 22% water.

The HCN-free acetonitrile/water mixture passing out of digester 24 is charged via line 30 into drying column 32. In addition, a stream comprising acetonitrile containing a small amount of heavy impurities is also charged into drying column 32 via line 34. In drying column 32, the acetonitrile/water mixture therein is distilled at a pressure below one atmosphere, e.g. 3.4 psia, to produce a bottoms product comprising water and heavy organics, which are discharged to waste via line 36, and a gaseous top draw comprising a second acetonitrile/water azeotrope, the second azeotrope containing about 10% water.

The second acetonitrile/water azeotrope is charged via line 38 into condenser 40 where it is condensed, passed via line 42 through heat exchanger 44 where it is heated, and then charged via line 46 into product column 48. In product column 48, the second acetonitrile/water azeotrope is distilled at high pressure, e.g. 50 psia, into three phases. A bottoms product comprising acetonitrile containing heavy impurities is withdrawn from the bottom of product column 48 and recycled via line 34 to drying column 32. A third acetonitrile/water azeotrope is withdrawn from the top of product column 48 and recycled via line 28 to digester 24 where it is mixed with the first acetonitrile/water azeotrope produced in heads column 16. Because product column 48 is operated at high pressure, all of the water in the second acetonitrile/water azeotrope charged into product column 48 is recovered in the overhead stream of product column 48, i.e. the third acetonitrile/water azeotrope, leaving high purity acetonitrile in the product column. This high purity acetonitrile (99.8 weight percent acetonitrile) is drawn off column 48 as a liquid sidestream via line 50, and after cooling in heat exchanger 44 is discharged as product via line 52.

From the above, it can be seen that the present invention very simply and easily produces high purity acetonitrile by distillation without using calcium chloride to remove water. Thus, waste disposal problems associated with the prior art techniques are largely eliminated.

Although only a single embodiment of the invention has been described above, many modifications can be made without departing from the spirit and scope of the invention. For example, instead of an aqueous solution of sodium hydroxide and formaldehyde, any other chemical which will destroy HCN without adversely affecting the acetonitrile product can be used as the HCN digester fed to digester 24. In addition, other pressures than those described above can be used in the three distillation columns of the invention. For example, the pressures in the heads column, drying column and product column can be 15 to 25 psia, 0.1 to 10 psia and 15 to 100 psia, respectively, with the pressure in the product column preferably being at least 5 psi greater than the pressure in the heads column. More preferably, the pressures in the heads, drying and product columns are 16 to 20 psia, 3 to 4 psia and 40 to 55 psia, respectively. All such modifications are intended to be included within the scope of the invention, which is to be limited only by the following claims.

Claims (12)

We claim:
1. A continuous process for recovering highly pure acetonitrile from crude acetonitrile by-produced during amoxidation of propylene containing acetonitrile, water, HCN and heavy organics, said process comprising:
(1) distilling said crude acetonitrile in a first distillation zone at a first pressure at or above 1 atmosphere to remove HCN therefrom and produce a first acetonitrile/water azeotrope and a first bottoms product containing water,
(2) distilling said first azeotrope in a second distillation zone at a second pressure less than 1 atmosphere to separate said first azeotrope into a second bottoms product containing water and a second acetonitrile/water azeotrope having a greater acetonitrile concentration than said first azeotrope, and
(3) distilling said second acetonitrile/water azeotrope in a third distillation zone at a third pressure above 1 atmosphere to produce a third acetonitrile/water azeotrope containing substantially all of the water in said second azeotrope, third bottoms product comprising acetonitrile and heavy organics and a sidestream comprising said highly pure acetonitrile of at least 95%.
2. The process of claim 1 further comprising recycling said third bottoms product to said second distillation zone.
3. The process of claim 2 further comprising recycling said third azeotrope to said second distillation zone.
4. The process of claim 3 wherein said third azeotrope is mixed with said first azeotrope prior to charging into said second distillation zone.
5. The process of claim 4 wherein an HCN digester is added to the mixture of said first azeotrope and third azeotrope prior to charging said mixture into said second distillation zone.
6. The process of claim 3 further comprising condensing said second azeotrope and thereafter heating the condensed second azeotrope prior to charging of said second azeotrope into said third distillation zone, said second azeotrope being heated by indirect heat exchange with said sidestream.
7. The process of claim 3 wherein said first pressure is about 15 to 25 psia, said second pressure is about 0.1 to 12 psia and said third pressure is about 15 to 100 psia.
8. The process of claim 7 wherein said third pressure is at least 5 psi greater than said first pressure.
9. The process of claim 8 wherein said first pressure is about 16 to 20 psia, said second pressure is about 3 to 4 psia and said third pressure is about 40 to 55 psia.
10. The process of claim 1 wherein said HCN is removed from said first distillation as an over-head stream and further wherein said first acetonitrile/water azeotrope is removed from said first distillation zone as a side stream.
11. The process of claim 10 wherein said crude acetonitrile is a by-product produced during the ammoxidation of propylene.
12. A process for recovering highly pure acetonitrile from a first acetonitrile/water mixture by-produced during amoxidation of propylene containing about 15 weight percent or more water comprising:
(1) distilling said first mixture in a first distillation zone at a first pressure below 1 atmosphere to produce a water-containing bottoms product and a second acetonitrile/water mixture comprising an azeotrope of acetonitrile and water more concentrated in acetonitrile than said first mixture,
(2) distilling said second mixture at a second pressure above 1 atmosphere to produce a third acetonitrile/water mixture comprising an azeotrope of acetonitrile and water less concentrated in acetonitrile than said second mixture and said highly pure acetonitrile of at least 95%, and
(3) recycling said third mixture so that said third mixture is distilled along with said first mixture.
US06222196 1981-01-02 1981-01-02 Continuous acetonitrile recovery process Expired - Lifetime US4362603A (en)

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US06222196 US4362603A (en) 1981-01-02 1981-01-02 Continuous acetonitrile recovery process

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Application Number Priority Date Filing Date Title
US06222196 US4362603A (en) 1981-01-02 1981-01-02 Continuous acetonitrile recovery process
DE19813168979 DE3168979D1 (en) 1981-01-02 1981-12-23 Process for the continuous recovery of acetonitrile
EP19810306095 EP0055920B1 (en) 1981-01-02 1981-12-23 Process for the continuous recovery of acetonitrile
KR810005227A KR880000891B1 (en) 1981-01-02 1981-12-30 Process recovery acetonitrile
ES508434A ES8304928A1 (en) 1981-01-02 1981-12-30 "A continuous process for recovering highly pure acetonitrile crude acetonitrile".

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KR (1) KR880000891B1 (en)
DE (1) DE3168979D1 (en)
EP (1) EP0055920B1 (en)
ES (1) ES8304928A1 (en)

Cited By (26)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1993023366A1 (en) * 1992-05-21 1993-11-25 Cryodyne Technologies Inc. Method for purification of acetonitrile
US5346595A (en) * 1993-02-23 1994-09-13 Alliedsignal Inc. Process for the purification of a pentafluoroethane azeotrope
US5426208A (en) * 1992-05-21 1995-06-20 Cryodyne Technologies, Inc. Method of purification of acetonitrile
EP0890572A1 (en) * 1997-07-08 1999-01-13 The Standard Oil Company Purification of acetonitrile by a distillative recovery/ion exchange resin treatment process
US6326508B1 (en) * 1998-02-23 2001-12-04 The Standard Oil Company Purification and recovery of acetonitrile
WO2002006212A3 (en) * 2000-07-18 2002-05-23 Standard Oil Co Process for the purification and recovery of acetonitrile
US6395142B1 (en) 1999-10-14 2002-05-28 Chemcycles, Inc. Method and apparatus for purifying low grade acetonitrile and other constituents from hazardous waste
CN1105099C (en) * 1997-08-05 2003-04-09 标准石油公司 Purification of acetonitrile by distiliative recovery/ion exchange resin treatment process
US20040176631A1 (en) * 1996-04-10 2004-09-09 Cesa Mark Clark Purification of acetonitrile by a distillative recovery/ion exchange resin treatment process
US20040230059A1 (en) * 2003-01-07 2004-11-18 Cesa Mark C. Process for the recovery of oxazole
US6843890B1 (en) * 1999-07-23 2005-01-18 The Standard Oil Company Purification and recovery of acetonitrile from waste solvent acetonitrile
US20070037171A1 (en) * 2005-08-11 2007-02-15 Yi Lu Aptamer-based colorimetric sensor systems
US20070269821A1 (en) * 2006-03-16 2007-11-22 Debapriya Mazumdar Lateral flow devices
US20080073201A1 (en) * 2003-11-04 2008-03-27 Ucb, S.A. Acetonitrile Recycling Process
US20080176228A1 (en) * 2000-06-27 2008-07-24 Yi Lu Nucleic acid enzyme biosensors for ions
US20090090894A1 (en) * 2007-10-05 2009-04-09 Bin Wang Separation and extraction system
US20090098550A1 (en) * 2007-07-31 2009-04-16 Yi Lu Mri contrast agents and high-throughput screening by mri
US20090143239A1 (en) * 2002-05-10 2009-06-04 Yi Lu Fluorescence based biosensor
US20090197261A1 (en) * 2007-04-24 2009-08-06 Yi Lu Aptamer- and nucleic acid enzyme-based systems for simultaneous detection of multiple analytes
US20100105039A1 (en) * 2008-06-03 2010-04-29 Yi Lu Label-free colorimetric detection
US20100166842A1 (en) * 2007-01-19 2010-07-01 Yi Lu Amphiphilic substances and functionalized lipid vesicles including the same
US20110123982A1 (en) * 2007-07-16 2011-05-26 Yi Lu Nucleic acid based fluorescent sensor for copper detection
US8062893B2 (en) 2008-10-10 2011-11-22 The Board Of Trustees Of The University Of Illinois Fluorescent sensor for mercury
US8367416B2 (en) 2007-08-10 2013-02-05 The Board Of Trustees Of The University Of Illinois Nucleic acid based fluorescent sensor for mercury detection
CN103224456A (en) * 2013-04-08 2013-07-31 江苏九天高科技股份有限公司 Process and device for refining acetonitrile with a pervaporation method
US8815156B2 (en) 2010-07-19 2014-08-26 Andalyze, Inc. Sensor housing and reagent chemistry

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GB1239460A (en) * 1967-11-08 1971-07-14
DE1920083A1 (en) * 1969-04-21 1970-01-29 Lentia Gmbh Continuously separating acrylonitrile and acetonitrile - from propylene/nh3/02 reaction prods
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Publication number Priority date Publication date Assignee Title
US3264197A (en) * 1961-05-27 1966-08-02 Chemie Linz Ag Process for the continuous recovery of acrylonitrile and acetonitrile by plural distillation and the addition of water

Cited By (45)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5292919A (en) * 1992-05-21 1994-03-08 Cryodyne Technologies, Inc. Method for purification of acetonitrile
US5426208A (en) * 1992-05-21 1995-06-20 Cryodyne Technologies, Inc. Method of purification of acetonitrile
WO1993023366A1 (en) * 1992-05-21 1993-11-25 Cryodyne Technologies Inc. Method for purification of acetonitrile
US5346595A (en) * 1993-02-23 1994-09-13 Alliedsignal Inc. Process for the purification of a pentafluoroethane azeotrope
US7491838B2 (en) * 1996-04-10 2009-02-17 Ineos Usa Llc Purification of acetonitrile by a distillative recovery/ion exchange resin treatment process
US20040176631A1 (en) * 1996-04-10 2004-09-09 Cesa Mark Clark Purification of acetonitrile by a distillative recovery/ion exchange resin treatment process
EP0890572A1 (en) * 1997-07-08 1999-01-13 The Standard Oil Company Purification of acetonitrile by a distillative recovery/ion exchange resin treatment process
CN1105099C (en) * 1997-08-05 2003-04-09 标准石油公司 Purification of acetonitrile by distiliative recovery/ion exchange resin treatment process
US6326508B1 (en) * 1998-02-23 2001-12-04 The Standard Oil Company Purification and recovery of acetonitrile
US6843890B1 (en) * 1999-07-23 2005-01-18 The Standard Oil Company Purification and recovery of acetonitrile from waste solvent acetonitrile
US6508917B1 (en) 1999-10-14 2003-01-21 Chemcycles, Inc. Method and apparatus for purifying low grade acetonitrile and other constituents from hazardous waste
US6395142B1 (en) 1999-10-14 2002-05-28 Chemcycles, Inc. Method and apparatus for purifying low grade acetonitrile and other constituents from hazardous waste
US20110171635A1 (en) * 2000-06-27 2011-07-14 Yi Lu Nucleic acid enzyme biosensors for ions
US20080176228A1 (en) * 2000-06-27 2008-07-24 Yi Lu Nucleic acid enzyme biosensors for ions
US8206915B2 (en) 2000-06-27 2012-06-26 Board Of Trustees Of The University Of Illinois Nucleic acid enzyme biosensors for ions
US7902353B2 (en) 2000-06-27 2011-03-08 The Board Of Trustees Of The University Of Illinois Nucleic acid enzyme biosensors for ions
WO2002006212A3 (en) * 2000-07-18 2002-05-23 Standard Oil Co Process for the purification and recovery of acetonitrile
US6780289B2 (en) * 2000-07-18 2004-08-24 The Standard Oil Company Process for the purification and recovery of acetonitrile
US8043802B2 (en) 2002-05-10 2011-10-25 The Board Of Trustees Of The University Of Illinois Fluorescence based biosensor
US20090143239A1 (en) * 2002-05-10 2009-06-04 Yi Lu Fluorescence based biosensor
US7906320B2 (en) 2002-05-10 2011-03-15 The Board Of Trustees Of The University Of Illinois Fluorescence based biosensor
US20040230059A1 (en) * 2003-01-07 2004-11-18 Cesa Mark C. Process for the recovery of oxazole
US7211674B2 (en) 2003-01-07 2007-05-01 Ineos Usa Llc Process for the recovery of oxazole
US20080073201A1 (en) * 2003-11-04 2008-03-27 Ucb, S.A. Acetonitrile Recycling Process
US7892734B2 (en) 2005-08-11 2011-02-22 The Board Of Trustees Of The University Of Illinois Aptamer based colorimetric sensor systems
US20070037171A1 (en) * 2005-08-11 2007-02-15 Yi Lu Aptamer-based colorimetric sensor systems
US20110236991A1 (en) * 2005-08-11 2011-09-29 Yi Lu Aptamer-Based Colorimetric Sensor Systems
US8470532B2 (en) 2005-08-11 2013-06-25 The Board Of Trustees Of The University Of Illinois Aptamer-based colorimetric sensor systems
US7799554B2 (en) 2006-03-16 2010-09-21 The Board Of Trustees Of The University Of Illinois Lateral flow devices
US20070269821A1 (en) * 2006-03-16 2007-11-22 Debapriya Mazumdar Lateral flow devices
US20100166842A1 (en) * 2007-01-19 2010-07-01 Yi Lu Amphiphilic substances and functionalized lipid vesicles including the same
US8415461B2 (en) 2007-01-19 2013-04-09 The Board Of Trustees Of The University Of Illinois Amphiphilic substances and functionalized lipid vesicles including the same
US20090197261A1 (en) * 2007-04-24 2009-08-06 Yi Lu Aptamer- and nucleic acid enzyme-based systems for simultaneous detection of multiple analytes
US8058415B2 (en) 2007-04-24 2011-11-15 The Board Of Trustees Of The University Of Illinois Aptamer- and nucleic acid enzyme-based systems for simultaneous detection of multiple analytes
US20110123982A1 (en) * 2007-07-16 2011-05-26 Yi Lu Nucleic acid based fluorescent sensor for copper detection
US8409800B2 (en) 2007-07-16 2013-04-02 The Board Of Trustees Of The University Of Illinois Nucleic acid based fluorescent sensor for copper detection
US20090098550A1 (en) * 2007-07-31 2009-04-16 Yi Lu Mri contrast agents and high-throughput screening by mri
US8568690B2 (en) 2007-07-31 2013-10-29 The Board Of Trustees Of The University Of Illinois MRI contrast agents and high-throughput screening by MRI
US8367416B2 (en) 2007-08-10 2013-02-05 The Board Of Trustees Of The University Of Illinois Nucleic acid based fluorescent sensor for mercury detection
US20090090894A1 (en) * 2007-10-05 2009-04-09 Bin Wang Separation and extraction system
US20100105039A1 (en) * 2008-06-03 2010-04-29 Yi Lu Label-free colorimetric detection
US8062893B2 (en) 2008-10-10 2011-11-22 The Board Of Trustees Of The University Of Illinois Fluorescent sensor for mercury
US8815156B2 (en) 2010-07-19 2014-08-26 Andalyze, Inc. Sensor housing and reagent chemistry
CN103224456A (en) * 2013-04-08 2013-07-31 江苏九天高科技股份有限公司 Process and device for refining acetonitrile with a pervaporation method
CN103224456B (en) * 2013-04-08 2015-04-22 江苏九天高科技股份有限公司 Process and device for refining acetonitrile with a pervaporation method

Also Published As

Publication number Publication date Type
EP0055920A3 (en) 1982-09-22 application
ES508434D0 (en) grant
DE3168979D1 (en) 1985-03-28 grant
EP0055920B1 (en) 1985-02-13 grant
KR830007525A (en) 1983-10-21 application
ES508434A0 (en) 1983-03-16 application
ES8304928A1 (en) 1983-06-16 application
EP0055920A2 (en) 1982-07-14 application
KR880000891B1 (en) 1988-05-30 grant

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